Paper folding mechanism

Details Paper folding mechanism Paper folding mechanism

2000-11-30

2003-01-28

Rada, Rinaldi I. (Department: 3721)

Manufacturing container or tube from paper; or other manufacturi

Bending

Folding

C493S430000, C493S433000, C493S448000, C493S431000

Reexamination Certificate

active

06511408

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a paper folding mechanism used for e.g. an electrophotographic printer. More specifically, it relates to a paper folding mechanism for alternately folding continuous recording paper to be stacked in a paper stacker disposed at the end of the paper transfer path of a printer.
2. Description of the Related Art
Conventionally, various kinds of paper folding mechanisms have been used for electrophotographic printers.
FIG. 12
of the accompanying drawings shows an example of conventional folding mechanisms.
Specifically, the illustrated conventional paper folding mechanism
200
includes a swing guide
1
, a plurality of first paper guides
102
a
and a plurality of second paper guides
102
b
. The swing guide
1
, supported by a driving shaft
14
, is caused to swing between the first and the second paper guides
102
a
,
102
b
. The paper guides
102
a
and
102
b
are fixed, at their upper ends, to a first frame
110
a
and a second frame
110
b
, respectively, to be held in an upright position. The first paper guides
102
a
are spaced from the counterpart second paper guides
102
b
by a distance equal to the “sheet length” (defined below) of continuous paper.
Referring to
FIG. 11
, a typical example of continuous recording paper is shown, which is equally usable for the conventional folding device and a device of the present invention. The illustrated paper P is formed with a series of indexing holes P
1
disposed at regular intervals along each longitudinal edge Pa and Pb. Further, the paper P is provided with a plurality of fold lines (perforation lines) P
2
each of which extends across the paper P. These perforation lines P
2
are spaced from each other longitudinally of the paper P by a constant pitch or “sheet length” L. The continuous paper P can be readily severed into separate paper sheets due to the perforation lines P
2
. Different types of continuous paper may have a different width W and/or sheet length L.
The conventional paper folding mechanism
200
further includes a vertically movable stacker table T, a plurality of first rotary blades
103
a
and a plurality of second rotary blades
103
b
. The printed recording paper, after being folded by the first or second blades, is piled on the stacker table T. The first rotary blades
103
a
are attached to a first driving shaft
104
a
and arranged adjacent to the first paper guides
102
a
, while the second rotary blades
103
b
are attached to a second driving shaft
104
b
and arranged adjacent to the second paper guides
103
b
. The first driving shaft
104
a
is rotatably attached to the first frame
110
a
, while the second driving shaft
104
b
is rotatably attached to the second frame
110
b.
As shown by the two-headed arrow Ar in
FIG. 12
, the first frame
110
a
is movable toward or away from the second frame
110
b
, whereby the first paper guides
102
a
, which are carried by the fist frame
110
a
, can be moved closer to or farther away from the counterpart second paper guides
102
b
. Such an adjustable guide distance between the first and the second paper guides is advantageous to dealing with various types of continuous paper having different sheet lengths L.
In operation, the swing guide
1
is caused to swing about the axis of the shaft
14
. In synchronism with this swing motion, a predetermined length of the paper P will be paid out from the guide
1
. Thus, the paid-out portion of the paper P will be warped near the first paper guides
102
a
or second paper guides
102
b
(see FIG.
13
). Then, with the paper P being thus warped, the first rotary blades
103
a
or second rotary blades
103
b
will hit upon the warped paper portion, thereby folding the paper P along the perforation line P
2
. As the volume of the paper P stacked on the stacker table T increases, the table T is lowered, so that the first and the second rotary blades
103
a
,
103
b
can hit the paper P properly for folding the paper.
In the conventional paper folding mechanism, as stated above, the first paper guides
102
a
and the first driving shaft
104
a
are attached to the same movable frame
110
a
. Thus, the positional relation between the guides
102
a
and the shaft
104
a
will remain the same before and after the first frame
110
a
is moved in the directions of arrow Ar. This unchanging positional relation renders the conventional paper folding mechanism disadvantageous in the following points.
For clarifying the problem of the conventional paper folding mechanism, it is now supposed that use is made of continuous paper having a relatively long sheet length L. In this case, as shown in
FIG. 13
, the distance between the first and the second paper guides
102
a
,
102
b
will be increased in accordance with the sheet length L, to accommodate the folded paper. Also, a relatively great length of paper is paid out from the swing guide
1
for performing one paper-folding operation by the first or second rotary blades.
In such an instance, as shown in
FIG. 13
, the paid-out paper P tends to be warped with a rather great radius of curvature. As a result, the warped portion of the paper P may fail to come close enough to the rotary blades
103
a
, so that the warped portion will merely be pushed toward the second paper guides
102
b
by the blades
103
a
without being folded at all.
Another example of erroneous paper-folding in the conventional mechanism is shown in FIG.
14
. Specifically, being partially folded, the paper P may suffer from a wrinkle N generated at a fold line P
2
. Such a defect may often be observed when solid printing is performed across the perforation line P
2
, since the solid printing portion tends to prevent the paper P from being properly folded.
SUMMARY OF THE INVENTION
The present invention has been proposed under the circumstances described above. It is, therefore, an object of the present invention to provide a paper folding mechanism designed to overcome the above conventional problems.
According to the present invention, there is provided a paper folding mechanism for continuous paper provided with fold lines spaced by a constant sheet length. The folding mechanism includes: a swing guide caused to pivot for guiding the paper; a first and a second paper guides spaced from each other by a guide distance corresponding to the sheet length, the first paper guide being displaceable relative to the second paper guide; and a paper presser arranged adjacent to the first paper guide for folding the paper along the fold lines. The paper presser is displaceable relative to the first paper guide.
With such an arrangement, it is possible to move the paper presser closer to or away from the continuous paper to be folded. Thus, by adjusting the position of the paper presser, a warped portion of the paper will be properly hit by the paper presser, which is advantageous to folding the paper properly.
In a preferred embodiment of the present invention, the paper presser may include a presser blade and a rotatable shaft to fix the presser blade. In this case, the shaft is displaceable relative to the first paper guide.
Preferably, the presser blade may include a free end portion and a base end portion fixed to the rotatable shaft, wherein the free end portion is more flexible than the base end portion. With such an arrangement, the paper is effectively prevented from being torn by the presser blade.
Preferably, the paper folding mechanism of the present invention may further include paper presser shifting means for displacing the paper presser relative to the first paper guide in accordance with displacement of the first paper guide. With such an arrangement, the paper presser can be automatically moved relative to the first paper guide. For instance, the paper presser shifting means may cause the paper presser to approach the first paper guide as the guide distance becomes greater.
Preferably, the paper presser shifting means may include a side plate for rotatably fixing the shaft, a lever pivotable relative to the

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